[otrs] OTRS installation on IIS?

Hi Guys, We have IIS server and running some other stuffs, it's impossible to us to have another server which just running Apache. I tried manually installing the OTRS on IIS server. I can install it with install.pl and everything seemed ok no error reported. But I just can't run it. Always get errors tell me module loading problem. Does any one have the experience to implement OTRS on IIS? How to get it work? Thanks a lot! Jack